Reclining chairs which rock in the upright position typically include a seat, arms, a back, and a curved rocker surface, which rocks on a base. Springs are used to restrain the movement of the rocker and to hold it in a fixed position when no one is sitting in it. A chair utilizing coil springs for restraining a rocker is disclosed in U.S. Pat. No. 3,163,464 issued Dec. 29, 1964 to Martin et al. The disadvantage of the disclosed chair is that the coil springs have no central pivot and allow unwanted movement of the rocker in relation to the base. Also, because of the non-rigid mounting of conventional springs, the use of a rocker blocking device is sometimes ineffective. The force on the rocker blocking device to contain the rocking motion of the chair is so great that it overcomes the force provided by the rocker springs and allows the base to shift in a forward or rearward direction. Furthermore, with conventional rockers several different extension-type coil spring gauges are needed to achieve desired forward and rearward rocking characteristics, thereby creating a problem with interchangeability and replacement. The conventional rocker box must be stretched with a tool to preload the spring and then applied to the base and frame. In addition, the exact center of gravity must be determined and the springs attached in close proximity to that point. These factors make assembly of the chair somewhat difficult.
Leaf springs for controlling the motion of a rocking chair are disclosed in U.S. Pat. Nos. 75,246 issued Mar. 10, 1868 to Conant and 200,296 issued Feb. 12, 1878 to Hesse. These patents disclose rocking chairs wherein rocking motion is provided by a curved portion of the rocker rolling on the base. A leaf spring attached at its center to the base and at its ends to the rocker controls rocking movement. U.S. Pat. No. 169,228 issued Oct. 26, 1875 to Best contains a similar disclosure except that the center of the leaf spring is attached to a pivoting shaft. U.S. Pat. No. 252,031 issued Jan. 10, 1882 to Haman discloses a rocking chair with a leaf spring which is adjustable in position. U.S. Pat. No. 215,581 issued May 20, 1879 to Dann discloses a rocking chair having L-shaped wire springs for controlling motion.
It is a general object of the present invention to provide improved rocking chairs and reclining chairs with a rocking feature.
It is another object of the present invention to provide rocking chairs wherein a movable lower frame member pivots about a single axis of rotation relative to the base.
It is a further object of the present invention to provide rocking chairs with a rocker spring assembly which does not permit lateral, forward or rearward movement of a movable lower frame member in relation to the base.
It is a further object of the present invention to provide rocking chairs with a rocker spring assembly which is adjustable.